首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
A Canadian researcher has discovered that sound travels 【21】______ air more than one-half kilometer an hour slower than had b
A Canadian researcher has discovered that sound travels 【21】______ air more than one-half kilometer an hour slower than had b
admin
2010-07-06
30
问题
A Canadian researcher has discovered that sound travels 【21】______ air more than one-half kilometer an hour slower than had been believed. The discovery has surprised many engineers and scientists who learned they had been 【22】______ the wrong speed of sound for many years.
The speed of sound in air had been【23】______ to be three-hundred-thirty-one-point-two-nine meters a second. But Doctor George Wong found, 【24】______ accident, that the speed of sound is only three-hundred-thirty-one-point-one-three meters a second. That is a difference of about sixteen centimeters a second.
Doctor Wong is a member of the National Research Council of Canada. He was studying ways to 【25】______ exactly the sound created by microph ones. One of his experiments 【26】______ a number he could use to find the speed of sound. He was 【27】______ to learn that the speed of sound was slower than scientists had thought.
To explain the difference, Doctor Wong spent eighteen months 【28】______ past test research on the speed of sound. He finally found the 【29】______ of the difference. It was a mathematics mistake 【30】______ in Nineteen-Forty-Two by physicist H-C Hardy.
Doctor Wong’s 【31】______ does not mean a big change for the science of sound. This is 【32】______ Doctor Hardy and Doctor Wong measured the speed of sound for what is called" standard air".
Standard air exists only 【33】______ thought. It is a way for scientists to agree 【34】______ the same speed of sound. 【35】______ the air around us, standard air always has a temperature of zero degrees Celsius and the same atmospheric pressure 【36】______ the air at sea level. Standard air always has same amounts of nitrogen, oxygen, carbon dioxide and 【37】______ gases. And in standard air, the speed of sound does not change.
The change in the new speed of sound is 【38】______ small to affect the work of most sound scientists and engineers. But scientists say Doctor Wong’s discovery may 【39】______ improve instruments 【40】______ use the speed of sound to measure very short distances.
【35】
选项
A、Since
B、Like
C、For
D、Unlike
答案
D
解析
本句意为“和我们周围的空气不同,标准空气要保持在零摄氏度,并且要有与海平面空气相同的气压。”故应选D 。
转载请注明原文地址:https://kaotiyun.com/show/XyDd777K
本试题收录于:
公共英语四级笔试题库公共英语(PETS)分类
0
公共英语四级笔试
公共英语(PETS)
相关试题推荐
A=BOOK1B=BOOK2C=BOOK3D=BOOK4Whichbook(s)say(s)that….theclimateaffectsthefuturesustainablea
Childrenwhogriptheirpenstooclosetothewritingpointarelikelytobeatadisadvantageinexaminations,【C1】________toth
Whatisyourresponsibilitywhenyou,asaschoolprincipal,gettheteacher’sreport?
Accordingtothespeaker,whatareconveniencegoods?
HowhavetheoncereasonablypricedholidaysinEuropebecometoAmericans?WhatcansolveAmerica’sproblemoftradeimbalance
Whenwerethefirstx-raysdiscovered?
Aflighttoothersolarsystemswillbemademorepossibleby______.Itispredictedthatpeoplewhowillliveonotherplanet
Asaresultofrisinguniversitycosts,whataremanystudentsfindingitnecessarytodo?
Manyofthemostdamagingandlife-threateningtypesofweather--torrentialrains,severethunderstorms,andtornadoes--beginqu
Who’stoblame?ThetrailofresponsibilitygoesbeyondpoormaintenanceofBritishrailways,sayindustrycritics.Stingygover
随机试题
【适应证】阿米巴肝脓肿、细菌性肝脓肿。【禁忌证】1.严重出血倾向或凝血功能障碍病人。(3)若行诊断性腹腔灌洗术,在腹中线上取穿刺点。4.常规消毒皮肤,术者戴无菌手套,铺无菌孔巾,并用1%~2%普鲁卡因2mL做局麻,
下列哪项对急性肾炎活动期的治疗员重要
A.红细胞管型B.白细胞管型C.脂肪管型D.颗粒管型E.肾小管上皮细胞管型肾病综合征
女,15岁。反复双下肢对称性皮肤瘀点、瘀斑,伴有四肢关节肿痛,有血尿和水肿。血小板计数正常。最可能的诊断为
足月儿,有窒息史,生后第2天嗜睡,面色微绀,呼吸频率32次/分,心率95次/分,前囟紧张,心音较低钝,四肢肌张力差,拥抱反射消失。最可能的诊断是
主张教师不再向学生传授系统知识,而是辅导学生自学和独立作业的教学组织形式是()。
过电压的能量来源于系统本身,其幅值与系统标称电压()。
我国学校普遍实行班级授课制的时间是()年。
我国行政管理的权力结构的特征是:
下列情形中,形成民事法律关系的是:
最新回复
(
0
)